Pressure-control apparatus



June 11, 1929. y L, 1,117,213

.rnnssunn CONTROL APPARATUS Filed-June 25, 1927 Inventor: Eugene L. Hough,

y M His A-tiso-wrweg+ Patented June 11, 1929.

UNITED STATES PATENT OFFICE.

EUGENE L. HOUGH, OF ST. LOUIS, MISSOURI, ASSIGNOR TO GENERAL ELECTRTC COM PANY, A CORPORATION OF NEW YORK.

PRESSURE-CONTROL APPARATUS.

Application filed June 23,

My invention relates to apparatus for maintaining the pressure of a highly evacuated vessel below a predetermined value, and has for its principal object the provision of an improved apparatus and method of operation whereby such apparatus is controlled 'in accordance with variations in this pressure.

In the operation of a vacuum device, such as the mercury arc rectifier, it is desirable that .the pressure within-the rectifier tank be maintained below a predetermined value, and that the pumping apparatus through which the gas is drawn from the tank be highly exhausted before it is connected to the tank. In accordance with my invention, these results are produced by an apparatus which starts to operate in response to a predetermined pressure rise within the highly evacuated tank and permits the connection of the vacuum pump to the tank only when it is in a condition to prevent the leakage of gas into the tank.

My invention will. be better understood from the following description when considered in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

The drawing shows a pressure control ap paratus wherein my invention has been embodied.

This apparatus comprises a vacuum pump 1 which is arranged to be driven by a motor 2 and to have its suction opening connected to a rectifier tank 3 through a valve 4. controlled-by a solenoid 5. Current for operating the pump 1 and valve 4 is supplied through suitable busses 6 and is controlled by a plurality of switches 7 to 12. Operation of the switches 7 to 10'is controlled by a vacuum responsive device 13 which may be of any suitable type, for example, such as that disclosed by United States Letters Patent No. 1,274,635, and is arranged to respond to variation in the pressure within the tank-3. The device 13 is provided with electrical leads 17 and a movable contact member 14 arranged to engage a contact 15 and produce closure of the switches 7 and 8 when the pressure within the tank 3 has risen to its highest permissible value. Operation of the switch 11 is controlled by a centrifugal device 16 mounted on the shaft of the pump 1, and operation of the switch 12 is controlled in accordance with 1927. Serial No. 200,973. v

the position of the valve 4. It will be readily and the contact member 14 to have moved into understood that avacuum pumpof the mer- I engagement with the contact 15, switches 7 and 8 are operated to their closed positions thus connecting the operating coil 'of'the switches 9 and 10 to the busses 6 and causing the motor 2 to be connected to these busses through the switch 10. When the motor 2 has attained its normal speed, the switch 11 is closed, the operating coil of the valve 4 is connected to the busses 6. through the switches 8 and 11, the switch 12 is closed, and a holdin r circuit for the operating coil of the switch 10 is completed between the busses 6 through the switches 9 and 12. Under these conditions, the pump 1 is connected to the tank 3 through the valve 4;.

Deenergization of the motor 2 while the valve 4 is open is prevented by the holding circuit which is interrupted only when the valve 4 closesand opens the switch 12. The leakage of gas into the tank 3 through the valve 4 is thus prevented under all conditions of operation and evacuation of the tank when the pressure of the gas within it attains a predetermined value is ensured.

\Vhat I claim as new and-desire to secure by Letters Patent of the United States, is: I

1. The combination of a closed receptacle, a valve, a vacuum pump arranged to be con nected to said receptacle through said valve, means responsive to the pressure of the gas within said receptacle for controlling the operation of said pump, and means operable in accordance with the position of said valve for causing said pump to be deenergized only when said valve is closed.

2. The combination of a closed receptacle, a valve, a vacuum pump aranged to be connected to said receptacle through said valve, means responsive to the pressure of the gas within said receptacle for controlling the operation of said pump, and a centrifugal device arranged to complete an electrical connection -3. The combination of a closed receptacle,

a valve, a vacuum pump aranged to be connected to said receptacle through said valve, means responsive to the pressure of the gas Within said receptacle for controlling the operation of said pump, a centrifugal device arranged to cause said valve to be opened only when the speed of said pump has attained a predetermined value, and means controlled by said valve for causing said pump to be deencrgized only when said valve is closed.

4. The combination'of a. receptacle, a valve. a vacuum pump arranged to be connected to said receptacle through said valve, an electric motor for operating said pump, means comprising a switch provided with an operating coil arranged to cause said motor to be energized when the pressure Within said receptacle attains a predetermined value, and a switch operated by said valve tocomplete a holding circuit for said operating coil.

5. The combination of a receptacle, a valve, a vacuum pump arranged to be connected to said receptacle through said valve, an electric motor for operating said pump, means comprising a switch provided with an operating coil arranged to cause said motor to be energized when the pressure Within said receptacle attains a predetermined value, means responsive to the speed of said motor for controlling the operation of said valve, and means operated through said valve for controlling a holding circuit for said operating coil.

In witness whereof, I have hereunto set my hand this twentieth day of June, 1927.

EUGENE L. HOUGH. 

